Crystal for non-cemented mounting in watch case bezel



M y 1955 F. FENGLER 2,709,333

CRYSTAL FOR NON-CEMENTED MOUNTING IN WATCH CASE BEZEL Filed June 10,1952 Tlg 23927501.:

CRYSTAL FOR N ON -CEMENTED MOUNTING IN WATCH CASE BEZEL FerdinandFengler, Bristol, Conn, assigncr to The E. Ingraham Company, Bristol,Conn, a corporation of Connecticut Application June 16 1952, Serial No.292,673 Claims. (Cl. 53--9l) This invention relates to crystals forindicators in general, and for timepieces such as watches in particular.Crystals for timepieces, and especially for wrist watches, arecustomarily cemented in the usual apertures in the bezels of the watchcases. However, while crystals thus cemented in place are generallysatisfactory, their pens frequently that the best available crystal fitsthe bezel aperture with less than the required accuracy, but isnevertheless cemented therein, with the result that the crystal may soonbecome loose and fall from the bezel. The task of accurately fitting abezel aperture with a crystal from an available supply of crystalsbecomes even more difiicult when the bezel aperture is non-circular inshape, in which case one has to content also with slight variations inthe shape of the crystals in addition to the usual tolerances in theirsize. The further task of applying cement to a chosen crystal andplacing the latter in the intended bezel aperture requires dexterity andexperience on the part of a watchmaker or repairman, and his furtherattention is usually required after the cement is dry when he may testthe crystal for the security of its mounting and also remove unsightlyexcess cement, if any. Further, even if modern non-breakable plasticcrystals originally fit accurately, and are securely cemented, in thebezels of watch cases, they will shrink, with age, to such an extentthat they are no longer dustproof and eventually fall out of the bezelsin which they are mounted.

Accordingly, it is a primary object of the present invention to providea crystal which may be mounted in a bezel without encountering any ofthe aforementioned diiiiculties.

Thus, it is an object of the present invention to provide a crystalwhich may be mounted in the usual bezel aperture of a watch case, forinstance, without the use of any cement whatever.

It is another object of the present invention to have provisions on acrystal for its ready interlock with the edge of the usual bezelaperture of a Watch case so that its mounting in the bezel is far moresecure than that of a cemented-in crystal.

t is a further object of the present invention to have theaforementioned interlock provisions on a somewhat resilient crystal sothat the latter may be mounted instantaneously by simply forcing thesame into the bezel aperture of a watch case until it snaps intoself-locking relation with the edge of the bezel aperture.

Another object of the present invention is to provide crystals which mayhave a relatively wide range of toler- The average Watchmaker or repair-.case itself forms no 2,739,333 Patented May 31, 1955 ice ances, andwhich are nevertheless securely mountable in the bezel apertures ofwatch cases in the aforementioned forced fashion.

A further object of the present invention is to make the somewhatresilient crystals of slightly larger size than the bezel apertures forwhich they are intended, so that the crystals Will in their mountedcondition be slightly stressed and, accordingly, have a tight anddustproof lit in the respective bezel apertures.

It is another object of the present invention to provide a somewhatresilient crystal of this type which may be intended for a bezelaperture of any shape, and which will, when being mounted in theaforementioned manner, conform to and fit accurately and in dustprooffashion in the bezel aperture despite slight variations in the shapes ofthe crystal and bezel aperture.

it is a further object of the present invention to provide a crystal ofthis type which may be mounted in the aforementioned manner withoutrequiring any special skill or special tools, so that persons other thanwatchmakers or repairmen may successfully perform the task.

It is still another object of the present invention to provide a crystalof this type which lends itself to simple molding and, accordingly, toefiicient mass production at low cost.

Further objects and advantages will appear to those skilled in the artfrom the following, considered in conjunction with the accompanyingdrawings.

In the accompanying drawings, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

Fig. l is a front View of a watch case with a mounted crystal in whichthe present invention is embodied;

Fig. 2 is a side view of the same watch case;

Fig. 3 is a section taken on the line 33 of Fig. 1;

Fig. 4 is a front view of the crystal alone;

Fig. 4A is an enlarged fragmentary section taken on the line 4A4A ofFig. 4; and

Fig. 5 is a front view of a differently shaped watch case with a mountedcrystal which also embodies the present invention.

Referring to the drawings, and more particularly to Figs. 1 to 3thereof, the reference numeral it) designates a watch case, in thisinstance a Wrist watch case, having an integral bezel 12 which isprovided with the usual aperture 14 for the reception of a crystal 16.The watch part of the present invention and may be conventional in everyrespect. The present invention is embodied in the crystal, and the samemay be used with equal advantage in bezels which are separate from orintegral with cases of timepieces in general and watches in particular.Accordingly, the invention will hereinafter be described with referenceto the bezel of a Watch case regardless of whether or not the bezel isseparate from or integral with the case.

The instant crystal 16 is of the non-breakable kind, i. e., it is madeof a suitable transparent plastic. The crystal 16, which in thisinstance is formed to fit in the circular aperture 1 5 in the bezel 12,is dish-shaped (Fig. 3) and comprises a web or bottom portion 13 and aprojecting rim portion 28. Formed integrally with the rim portion 29 ofthe crystal are a plurality, in this instance four, angularly spacedwedge-shaped outward projections 22, each of which terminates in ashoulder 24 at some distance from the open end 25 of the rim portion 2t;(see also Fig. 4A). More particularly, the wedge projections 22 slantoutwardly from the periphery of the rim portion 2%, and preferably fromthe smooth merger 27 of the latter and the web portion 18 of the crystal(Fig. 4A). The rim portion 20 of the crystal is further provided at itsopen end 25 with a plurality of integral flange-like outward projections26 which in this instance alternate with the wedge projections 22 (Fig.4). Of course, the flange-like projections 26 could, if desired, beformed continuous with each other in a single annular flange on the rimportion 2% of the crystal. in any event, the number and. spacing of theprojections 22 and 26 should be such as to afford a stable support forthe crystal in the bezel. The wall thickness of the preferably moldedplastic crystal to is substantially uniform throughout, and is such asto render the crystal somewhat resilient, especially in the web orbottom portion 18 thereof.

in mounting the instant crystal 16, the same is merely forced from theinside the bezel 12 in the direction of the arrow a into the aperture 14therein, by applying an outward force to the crystal with a suitabletool or tools, or even by hand. in thus forcing the crystal 16 into thebezel aperture 14, the wedge projections 22 on the crystal will reactwith the bezel aperture in resiliently flexing the web portions 18 ofthe crystal sufficiently to permit the wedge projections to pass throughand finally clear the bezel aperture (Fig. 3). When the wedgeprojections 22 clear the bezel aperture 14 on forced insertion of thecrystal into the latter, the Web portion 18 of the crystal permitted torecover, with the result that the rim portion 2% of the crystal willexpand and the flange projections 25 and shoulders 24 of the wedgeprojections 22 of the crystal will become securely interlocked with thebezel 52 (Fig. 3). Accordingly, the mounting of the crystal 1% in thebezel 12 requires no cement whatever, and is accomplished by merelyforcing the crystal into the bezel aperture until it snaps into thedescribed interlocl; with the bezel.

In order to provide a tight and dustproof fit between the crystal l6 andthe bezel aperture 14, the diameter of the crystal is preferablyslightly larger than that of the bezel aperture. With the crystal thusslightly larger than the bezel aperture, the web portion 18 of thecrystal will, in the mounted condition of the latter, be held under aslight permanent stress which is sufficient to hold the rim portion 2%against the edge of the bezel aperture 14 with sumcient force toaccomplish the objective of dust proof closure of the bezel aperture. inorder to facilitate the forced insertion of the crystal 16 into thebezel aperture 14, the web portion 18 of the crystal is fiat, or ispreferably formed slightly convex outwardly as shown in Figs. 2 and 3.

The instant crystal in is p rticularly advantageous in that no cementwhatever is required for its mounting. As compared to the task ofcementing a crystal in a bezel aperture, the mounting of the instantcrystal 16 is instantaneous and requires hoot j shill, it being merelynecessary to force the crystal into the bezel aperture until it becomesself-locked therein. The interlock of the mounted crystal with the bezel3.2 is also far more secure than the mounting of a cemented crystal, andshrinkage of the instant crystal with age, or differential expansion ofthe crystal and bezel under heat, will not adversely affect the securemounting of the crystal. The forced engagement of the rim port: 2% ofthe crystal with the bezel aperture 14, in consequ nce of the describedslight oversize of the crystal as compared to the bezel aperture and theresulting permanent stress in the Web portion of the mounted crystal,further affords a dustproof seal between the crystal and the bezelaperture. The wedge projections 22 on the crystal, which are exposed toview in the mounted condition of the latter, are preferably narrow (Fig.4) and also cross-sectionally curved, so that they are hardly noticeableand in nowise unsightly. As compared to cemented crystals which have tofit fairly accurately in the bezel apcrturcs for which they are intendedin order to achieve their mounting with any degree of security, theinstant crystal may, by virtue of its resilient mount in the bezelaperture, have relatively wide tolerances. The instant crystal may alsoreadily be molded. In this connection, the provision of the projections22 and 25 on the rim portion Zil of the crystal in the preferred fashionso that they do not overlap each other, makes it possible to moldcrystals of this type efficiently and at low cost in a simple two-partmold, as will be readily understood. Furfllfil, the circumferentiallyspaced relation of the projections 22. and 26 on the rim portion 2% ofthe crystal is further advantageous in that it leaves the rim portionsufficiently resilient to engage the bezel aperture 14 with an equalforce throughout.

ig. 5 shows a modified crystal 16 which differs from h L revlouslydescribed crystal it? primarily by its differn shape. Thus, the crystalin is, in this instance, generally oblong in outline so as to fit in acorrespondingly s" aped aperture 1d of a bezel 12'. The crystal 16 isdish-shaped similarly as the crystal to, and has on its rim portion 2%spaced integral wedge projections 22' which terminate in shouldersbearing against the bezel 12 on the outside thereof. The crystal 1% ison its rim portion 2%? further provided with spaced integral flangeprojections 26 which bear against the bezel 12 on the inside thereof.While circular crystals, such as the previously described crystal 16,will usually fit accurately in circular bezel apertures, non-circularcrystals, such as the oblong crystal 16, are more apt to deviateslightly in shape from that of the bezel apertures for which they areintended. However, the web and rim portions 18' and 20 of the crystal16' are sufliciently resilient to permit such slight deformation withoutof the crystal as is required in order that the latter may litaccurately and in dustproof fashion in a bezel aperture which is shapedsli htly different than the crystal.

The invention may be carried out other specific ways than those hereinset forth without departing from the spirit and essentialcharacteristics of the invention, and the present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming Within the meaning and equivalencyrange of the appended claims a e intended to be embraced therein.

What is claimed is:

l. A crystal and non-cemented mounting therefor in the aperture of abezel, comprising a transparent cover of slightly resilient materialhaving a web portion and an integral depending rim portion fittedlyreceived in said bezel aperture, said rim portion having a first set ofcircuinferentially spaced integral projections slanting wedgelikeoutwardly therefrom and terminating in shoulders, respectively,overlapping and bearing against the bezel at the outside thereof, andanother set of circumferentially spaced integral flange-like outwardprojections overlapping bearing against the bezel at the inside thereof.

2. A crystal and non-cemented mounting therefor as set forth in claim 1,in which the projections of one set are spaced from the projections ofthe other set circumfcrentially of said rim portion.

3. A crystal and nonemen'ted mounting therefor as set forth in claim 1,in which the projections of said first set are identical and few in numbr and their combined width circumferentiaily of said rim portion of thecover is only a small fraction of the circumferential dimension of saidrim portion, and the projections of said other set extendcircumferentially of said rim portion between successive projections,respectively, of said first set without overlapping the latterprojections.

4. A crystal for cement-less mounting in the aperture of a bezel,comprising a transparent cover of slightly resilient material having aweb portion and an integral de pending rim portion adapted for fittedreception in the bezel aperture, said rim portion having a first set ofcircumferentially spaced and axially extending integral projectionsslanting wedge-ll. e outwardly therefrom and terminating in shoulders,respectively, and another set of circumferentially spaced integralflange-like outward projections facing said shoulders and being spacedtherefrom axially of said rim portion, the projections of said first illset being adapted to react with the bezel opening in resiliently flexingsaid web portion on forced insertion of the cover into the bezelopening, and said shoulders and flange-like projections being adapted tointerlock with the bezel when the cover is inserted therein.

5. A crystal as set forth in claim 4, in which the projections of oneset are spaced from the projections of the other set circumferentiallyof said rim portion.

References Cited in the file of this patent UNITED STATES PATENTS1,918,987 Seabold July 18, 1933 6 Worden Oct. 19, 1937 Field Oct. 28,1941 Poupitch Jan. 9, 1951 Starke Aug. 19, 1952 FOREIGN PATENTS GreatBritain Apr. 9, 1914 Australia Jan. 9, 1941 Switzerland July 1, 1939Switzerland Apr. 16, 1940

